The purpose of the proposed research is to investigate the role of habitual dietary intake of fish, n-3 fatty acids of marine origin, and total fat in modifying risk of periodontal disease and the host inflammatory response. The primary goals of this study are to: (a) determine whether greater habitual dietary intake of fish and n-3 fatty acids of marine origin, as determined by food frequency questionnaires, is associated with decreased prevalence, extent, and severity of periodontal conditions in a middle-aged biracial cohort of men and women, (b) determine whether greater dietary intake of fish and n-3 fatty acids of marine origin is originated with reduced levels of prostaglandin E2 and thromboxane B2 measured locally in samples of gingival crevicular fluid, (c) determine whether greater habitual dietary intake of fish and n-3 fatty acids of marine origin is associated with reduced levels of C-reactive of C-reactive protein measured in serum, and (d) determine whether greater habitual dietary intake of total fat is associated with increased levels of prostaglandin E2 measured in gingival crevicular fluid. The study population will be the Atherosclerosis Risk in Communities Study (ARIC), a longitudinal investigation of cardiovascular disease, subclinical atherosclerosis, and associated risk factors in a cohort of 15,792 middle-aged men and women in four U.S. communities This research will take advantage of previously collected information on usual or habitual diet, prevalence, extent, and severity of periodontal conditions and levels of local and systemic inflammatory mediators and markers in members of the ARIC cohort. The proposed research will represent one of the largest epidemiologic studies of diet, periodontal disease, and mediators of inflammation and will provide new dat concerning potentially modifiable risk factors for periodontal disease and other chronic inflammatory conditions.